Veenstra 170 - Anxiety Disorders Association of America

It receives information directly from sensory systems before any higher level processing
It receives external info but in a quick and fuzzy form – just the gist of what it is encountering
But it also receives info from internal systems – it monitors heart & breathing rates, etc.
Amygdala is like the brain’s sentry – on guard for any possible danger
It is hard-­‐wired to unconsciously and reflexively trigger its emergency responses
Some stimuli are genetically programmed for their value to a specific species of animal
Rats can recognize cat dander; chickens can recognize hawk silhouettes
Human infants can be triggered by pain, difficulty breathing, loud noises, being dropped,
and by anger or anxiety on the faces of people they see
If it detects these dangers, it automatically triggers a whole series of inherited responses
At the body level, it triggers the arousal of the sympathetic autonomic nervous system that
enables emergency action by accelerating processes like breathing, heart rate & blood pressure, etc.
At the brain level, it triggers the release of neurotransmitters like norepinephrine and dopamine
that facilitate a similar acceleration of brain functioning
At the behavioral level, it produces survival responses like freezing and running
These are the responses that people experience when frightened that can now be explained
In mammals, the amygdala response is fed up to the paleocortex where:
it is translated into emotions that are used in mammalian problem solving and
it produces the distress cry that is instinctively programmed to communicate to mothers
Amygdala is a simple, reactive on-­‐switch
It has no capacity to evaluate dangers, it fires to all possible dangers
Amygdala cannot turn itself off – it has no off-­‐switch
In reptiles it can only be turned off by escaping the stimuli that is turning it on (humans also)
Mammals have no hard-­‐wired safety switch to turn off their arousal
But they have mammalian solution – fear triggers the distress cry which brings mother
and her presence produces calming that can be called the security switch.
As mammals mature they can begin to internalize mother’s security which will create a learned off-­‐switch
Change 2: What Is the Fear Trigger in Panic
Old: There doesn’t seem to be a trigger in panic – no external stimuli associated
New: Amygdala can learn to unconsciously associate internal stimuli with danger
Amygdala is where fear conditioning takes place
If amygdala is lesioned, then no fear conditioning, no autonomic arousal, & no feeling of fear
Amygdala learns by unconscious implicit stimuli conditioning – do not have to be conscious to learn
Amygdala can easily learn certain predisposed stimuli – like snakes, insects, blood, etc.
When external sensory stimuli is associated with amygdala arousal, will learn as phobia
The intensity of the amygdala arousal is taken as the validity of the association
If the arousal is intense, then can have one trial learning – “flashbulb memory”
So it is easy to learn false alarms (no real danger, but intense arousal) – superstitutious learning
Since amygdala monitors internal stimuli like heart rate, it can learn to view it as a fear stimuli
Interoceptive stimuli are usually the basis for panic attacks
Once learned, an intense fear conditioning circuit will be remembered for ever
Neuroscience Advances for Improving Anxiety Therapies © Glenn Veenstra 3